RFR: 8341831: PhaseCFG::insert_anti_dependences asserts with "no loads" [v3]

[Igor Veresov]

> `CacheWB` nodes are peculiar in a sense that they both are anti-dependent and produce memory. I think it's reasonable to relax the assert in `insert_anti_dependences()` to work around their properties.

Igor Veresov has updated the pull request incrementally with one additional commit since the last revision:

  Add comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21455/files
  - new: https://git.openjdk.org/jdk/pull/21455/files/b8e0d8bd..ae69ee4b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21455&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21455&range=01-02

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21455.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21455/head:pull/21455

PR: https://git.openjdk.org/jdk/pull/21455